How to use source_location in a variadic template function?

Question

The C++20 feature std::source_location is used to capture information about the context in which a function is called. When I try to use it with a variadic tem

Answer 1

Just put your arguments in a tuple, no macro needed.

#include 
#include 

template 
void debug(
    std::tuple args,
    const std::source_location& loc = std::source_location::current())
{
    std::cout 
        << "debug() called from source location "
        << loc.file_name() << ":" << loc.line()  << '\n';
}

And this works^*.

Technically you could just write:

template 
void debug(
    T arg, 
    const std::source_location& loc = std::source_location::current())
{
    std::cout 
        << "debug() called from source location "
        << loc.file_name() << ":" << loc.line()  << '\n';
}

but then you'd probably have to jump through some hoops to get the argument types.

---

_{* In the linked-to example, I'm using because that's what compilers accept right now. Also, I added some code for printing the argument tuple.}